This time White’s king is the one that seems quite secure; his castled position is undisturbed. But look at the strength of Black’s resources: he has two kernels of discovered attacks arranged against h2. Think about good ways to clear the knight and bishop from the paths of the heavy pieces—ways that allow the unmasking pieces to contribute to a mating attack. It's natural to start with a check, so Black begins with Ne2+; this forces White’s king to h1. Now the way is clear for Black to open the h-file with a sacrifice: Qxh2+, requiring KxQ. All that remains is for Black to move his bishop out of the way of his rook, which it needs to do anyway to complete the pattern for Greco’s mate: Bxf2#. But notice that Bg3 also is mate, since the knight on e2 still seals off g1 as a flight square and protects the bishop on g3. (A knight on e2 can be very powerful in mating patterns; we will study some that make more use of it soon.)